MLB draft picks aren't like bags of tomatoes

This isn't a particularly big deal, but I've recently seen a number of slight variations of what I'd consider some peculiar logic, in a question in MLBTR's new chat, in a recent Ken Rosenthal column, and elsewhere.

From MLBTR:

Comment From Neil Hunnington
Why didnt I sign Loshe when I have two 1st rnd picks?

Ben Nicholson-Smith: Draft picks aside there's still the question of whether Lohse is worth the dollars he's commanding.

Okay, okay -- it's not surprising that someone calling himself "Neil Hunnington" might not be thinking that clearly. But here's Rosenthal:

While it’s possible that Attanasio could negotiate directly with Lohse’s agent, Scott Boras, the Brewers will be reluctant to lose the No. 17 overall pick and corresponding slot money.

Lohse, who received a qualifying offer from the St. Louis Cardinals, is subject to such compensation. And the new collective-bargaining agreement leaves little opportunity for the Brewers to recoup a top pick through some other method.

I don't follow -- why is it okay to lose first-round draft picks as long as you have one left over? Draft picks aren't like homegrown tomatoes, where if you grow too many you have to sneak around leaving bags of them on your neighbors' porches. If you have one draft pick, you can help your farm system a given amount, and if you have two of them, you can help your farm system even more. Having more high draft picks is always a good thing, even if you already have two or three. You never risk wasting resources by having more, as you might if, for example, you had three potential starting catchers. The fact that the Pirates have the No. 9 overall pick next year has no bearing on the value they ought to place on the No. 14 pick, except insofar as they can't pick the player they picked at No. 9 twice.

We saw this argument a couple times when the Pirates traded their competitive balance pick for Gaby Sanchez -- some folks argued that the pick was expendable because the Bucs already had two earlier ones. Why would the Pirates having two previous first-round picks have any bearing on the value they would have been able to get at No. 33? The No. 33 overall pick in the draft has a certain value, both in terms of the opportunity to pick a player before anyone else does and in the amount of money in a team's draft pool. That value doesn't really decrease if you happen to have the No. 9 and No. 14 picks as well. The idea that a draft pick's value changes substantially when you hold other draft picks is silly, and I'd be very surprised if many teams actually thought that way.

As a side note, it doesn't make much sense for the Pirates to give up the No. 14 pick and pay a bunch of money to sign Kyle Lohse. You might be able to make the argument if the Pirates were one Kyle Lohse away from being a division winner, but that's a stretch.